Acute common peroneal nerve palsy caused by hemorrhage into a recurrent ganglion

Ganglia were first described by Hippocrates, as `knots of tissue' containing `mucoid flesh' (1). They occur most commonly at the wrist and occasionally at the knee. They usually present with pain and rarely cause compressive neuropathies. Hartwell (2) in 1901 first described peripheral nerve (median nerve) involvement by a ganglion. In 1921, Sultan (3) reported a patient with paralysis of the common peroneal nerve caused by a cystic tumour. In 1952, Brooks (4) described 13 patients who had peripheral nerve compression by simple ganglia. In three of these patients the common peroneal nerve was involved. Stack et al in 1965 (5) described nine cases of compression of the common peroneal nerve by ganglia arising from around the knee. Following this series by Stack et al (5), there were no more cases of common peroneal nerve compression reported in the literature, until a report in 1994 by Evans et al (6). In this case magnetic resonance imaging was emphasized as a useful diagnostic modality. We describe a case of acute common peroneal nerve compression neuropathy. The ganglion was recurrent following previous incomplete excisions. The acute compression was likely caused by hemorrhage into the ganglion. This case emphasizes the importance of early and complete surgical excision of ganglia around the fibula neck.